There are many ways to close and tighten footwear and medical immobilization devices, such as orthopedic boots and casts. A similar situation applies to bands, such as watchbands. Closing and opening mechanisms are important to the workings of many products, and to inanimate objects such as packages, and boxes. Examples of conventional means include laces, ties, buckles, straps, tensioners, and Velcro. These generally require significant manual intervention or manipulation to close, tighten, and open. Depending on an individual's physical abilities or disabilities, this may vary from being an inconvenience to being impossible.
Efforts have been made to provide self-tightening closure devices. For example, there have been attempts to use shape memory materials to facilitate self-tightening closures in shoes and other devices. Shape memory materials generally change between an original state (e.g., baseline, memorized, permanent) and a deformed state (temporary shape) by means of an external stimulus. For example, a shape memory polymer can exhibit change from a rigid state to an elastic state, then back to the rigid state using an external stimulus. In similar respects, a shape memory alloy is an alloy that remembers its original shape and, after undergoing deformation, can transform back to its pre-deformed, original shape when triggered to do so.
U.S. Pat. No. 6,598,322 describes a shoe having an elongated shape memory alloy element and an electric circuit which when energized will produce a tightening of the shoe upper around the foot of a wearer. A battery contained in the shoe provides a power source to produce a current in the circuit that heats the shape memory alloy causing it to reduce its length providing the tightening of the shoe uppers. The circuit is energized by a switch in the shoe heel that is turned on by the wearer clicking his heels together. While the shape memory laces can be tightened and loosened without intervention, they remain tied which may lead to some difficulty in putting the shoes on and taking them off.
Another means of self-tightening a shoe is described in U.S. Pat. No. 8,935,860. This reference describes a shoe having a sole and a shoe upper, wherein the shoe is provided with a mechanism for automatically tightening the shoe on a foot to a preset level of tightness. The shoe includes a pressure sensor in the heel of the shoe along with a memory chip which stores a desired fit. Rather than using a shape memory material, the '860 patent tightens the several shoe straps using an electric motor powered by a battery.
While these references provide some assistance with tightening, they do not address the difficulty of latching and unlatching a closure device. Having laces, bands, or closures that only tighten and loosen without completely opening up may not be sufficient for some users, particularly during ingress and egress of a body part. It is desired to provide an improved solution and particularly a solution that substantially reduces or eliminates the necessity for manual intervention.